Error when printing customized format for new module

Hi everyone,

Can somebody help me, I have created a new module in my erpnext version 13 and the name is “Memorial Park”. I created a new doctype under it called “PNPA Sales” and created new print format to print the customer ledger. But when I try to print using the print format it gives me a key error “memorial_park” (server error). I have tried to create a folder named “memorial_park” under \apps\erpnext\erpnext and a new folder named “print_format” under “memorial_park” but it didn’t solve the problem. Did I miss something? Please help. Thank you.